Rotary cutter



March 23 1926. 1,577,620

J. R. GAMMETER ROTARY CUTTER- Filed May 25, 1922 n v 2 Sheets-Sheet 1.

la f//m R. Gammejen www J. R. GAMMETER ROTARY CUTTER Filed'May 25, 19222 sheets-sheet 2 [nz/enfor- John R. Gammee? AMM El? Fatented Mar. 23,1926.

Tsui" Fries.

JOHN R. GAMMETER, OF KRON, OHIO, ASSIGNOR TO THE B. F. GOODRICH COMPANY,

. OF NEWMYORK, N. Y., .A CORPORATION' OF NEW YORK.

ROTARY CUTTER.

Application inea Mayas, 192e. serial No. 563,570.

Be it known that I, JOHN R. GAMME'rnn, a

citizen of the United States, residing at JA kroii, in the county ofSummit andState of Ohio, have invented a certain new and useful RotaryCutter, of which the following is a specilication.

"This invention relates to rotary cutters and more especially to cuttersof this character adapted to cut a. sheet of material on the bias, as inthe preparation ofrubberized fabricv for the manufacture of pneumatictires, wherein the cutting element comprises a iiexible knife or stripof metal wound helically upon the surface ofa drum, the presentinvention being'y an improvement upon that of my copending applicationSerial No. 474,320, filed. June 2, 1921. i

My general lobject is to provide an improved rotary lcutter ofeconomical l construction adapted for rapid and accurate work. A morespecific object is'to provide a cutter wherein a metal strip or knifehaving a plurality of cutting edges may be used, and vchanged inposition after eachedge is dulled so as to bring another edge into use.Another specific object is to provide an improved, resilient mountingforsuch a knife which will hold the knife accurately7 in place withoutdrilling its edges that are not at the Atime functioning as cuttingedges, and will avoid buckling of the knife.v Further 0bjects are toavoid upsetting or overturning forces upon a knife of the kind referredto, to assure the proper separation of the Work from the cutting drumafter the work is cut, and to provide a machine readily adaptable to cutthe work to different forms or sizes.

Of the accompanying drawings:

Fig. 1 is a diagrammatic end View of a rotary cutting drum and certainelements associated therewith, illustrating the use of myy improvements.

Fig. 2 is a side elevation, with parts broken away, of a cutting drumembodying a preferred form of my invention.

Fig. 3 is a transverse section through a part of the drum and a knifemounting and kknife thereon, online 3 3 of Fig. 2.

.Fig 11 is a plan view of a part 'of the `knife-inoi'inting shown in 8.

Fig. .is a section on line 10-10 of 9.( Y l i Fig. 11 is a section online 11-11 of Fig. 8.

Fig. `12 is a plan viewv yof a variable-speed' driving device, on aVsmall scale.

In the'drawings, 10 is a rotary, cylindrical drum on which are helicallywound a plurality Y of flexible strips of metal or knives 11, oftriangular cross-section, said knives being fastened at their ends, byadjustable anchor-bolts 12, 12, to bracket-like anchoring members 13, 18secured yon the respective ends of the drum. 111, y1&1 are helicalstrips of rubber or cushions constituting a resilient cover for saiddrum 'between said knives, for holding the work in substantiallycircular form between the knives so that deformation of the fabric isavoided and an accurate operation obtained. 15, 15 are strips ofnonsticking fabric `overlying said cushions to avoid adhesion of thework to the drum.

In Fig. 1, 16 is a hard-surfaced roll, preferably of metal, yagainstwhich roll the knives 11 are adapted to cut the rubberized fabric 17which constitutes the work, the latter passing partly around said rolltothe cutting position, and being pressed against said roll adjacent andbetween the'successive knives by the cushions 14. 18, 19, 20 are guiderolls, ovei which a liner 21, from any convenient source (not shown) isadapted to pass, being guided thereby partly around the cutting drum 10,as shown, and to a liner and stock rewinding roll 21a, said linercarrying with it from the cutting drum 10 the bias-cut strips of fabricas cut by the knives 10 actingagainst the hard rroll 16,

the liner and said strips being interwound together upon the roll 21a.rI`he liner .and stock rewinding roll 21a may be provided with anysuitable friction driving means (not shown) so as to receive the hnerand work as fast as they are given offby the drum 10, notwithstandingthe changing size of the body of liner and stock wound thereon.

The drum 10 is of such size with respect to the angle at which theknives 11 lie thereon that the hard roll 16 will pass off of the lastend of each knife before it again contacts .the leading end of the sameknife, so that it at no time bears upon more than one part of the sameknife. I thereby avoid such buckling of the middle portion of the knifeaway ,from the drum as is likely to occur if the knife is given morethan one complete turn about the drum and is thus inposition to have twoparts of it in contact with the roll 16 at the same time.

In the preferred embodiment shown in Figs.2, 34 and 4, the knife 11 isof equilateral, triangular cross-section, and is seated betweenflanges22, 22 upon the outer surface of a strip of hard rubber 23vulcanized to an underlying strip of soft rubber 2l, said strips havingside faces substantially radial to the drum 10 and being seated in agroove 25, of corresponding shape, in the drum, so as to constitute aresilient backing strip for the knife. Said backing strip is held in thegroove 25, preferably under compression, by plates 26, 26 screwed to theouter face of the drum 10.

The hard rubberstrip 23 is reinforced by a looped wire 27 embedded andvulcanized therein, the sinuous form of said reinforcement permittingthe vfree bending of the knife-backing strip about the drum whilestrengthening it laterally. The knife 11, being of equilateral,triangular cross-section, may be turned to bring a new cutting edge intoposition when one has become worn, and will fit snugly between theflanges 22, 22 in either position, seating upon one of its flat sides.The backing strip may be con stantly held under substantial compressionby the plates 26, so'as`to offer sufficient rcsistance toforce the knifethrough the work without excessive movement of the knife radially inwardwith respect to the drum, although yielding sufficiently to insurenroperycontact of all parts of the knife with the hard roll 16.

In the modification shown in Fig. 5, a knife 11 of square cross-sectionis seated in vcutting position on a metal strip 28 of bridge-like orarched form in cross-section, said strip being formed with a Vlgroove inits outer surface adapted to fit two sides of the square knife so as tohold it with one edge outward, in cutting position. The legs 28a, 28 ofthe arch are turned outward and formed with perforations inv which areslidably mounted screws 29, 29 passing throu h a cushion 30, of softrubber, underlying tIie metal strip 28, said screws being threaded intothe body of the drum 10, soV that said metal strip may slide on saidscrews, the pressure on the knife being resisted by the rubber cushion30. The archedfform of said strip may be adapted to provide resiliencein addition to that of the cushion 30. It affords a good seat vfor theknife, preventing lateral displacement or rolling of the latter, and maybe economically constructed, as by stamping or rolling a strip of sheetmetal.

In the modification shown in Fig.A 6, the knife-backing strip comprisesan outer hard rubber strip 32 vulcanized to an inner soft rubber strip32, and secured in the groove 25 by the plates 26, the constructionbeing similar to that of the lform shown in Fig. 3, except that thesquare knife 112L is used, the hard rubber strip 32 being appropriatelygrooved to receive it.

The modification shown in Fig. 7 issubstantially like the form shown inFig. 3, ex-

cept that a metal strip 28b is substituted for `the hard rubber strip23.

It is highly desirable, in the use of knives such as those described,that means for rapidly changing drums without danger of injury to theknives be provided, that an even pressure be maintained between thedrinn and the hard roll, and the drum 10 and hard roll 16 both bedriven, and at the same peripheral speed, `in order that the knives maynot'be overturned, laterally displaced, or dulled, bv relative movementbetween the knife and the surface of the hard roll with which itcontacts. In order that they may be so driven, as well as to obtain theother advantages mentioned, I prefer to mount them as shown in Figs. Sto 12, wherein 33 is the nearer of a pair of end standards for the hardroll 16, thc drum '10, and the liner guiding rolls 18, 19, 20. The hardroll 16 is journaled in a fixed position at the top of said standardsand one of its trunnions is provided with a sprocket 34: secured thereonand adapted to be driven by a chain 35.

Upon a reduced portion of each trunnion of the drinn 1() is mounted ajournal block 36, one of which, at the driving end of the roll, isretained thereon by a jaw clutch member 37 non-rotatably secured on afurther reduced portion of the trunnion by av key 3S and a set screw 39v(Fig. 11). said clutch member being adapted to interlock. as indicatedat 40, at its outer side, with the hub of a sprocket 11 mounted upon theend portion of the trunnion and detachably retained thereon ininterlocked engagement with the clutch member 37 bv a U-shapedspring-clip or clasp 42 adapted to be sprung onto the end of saidtrunnion, the latter being formed with a circumferential groove lili)lll) lil() 43 to receive the spring or tongue 44of said clasp. The rearjournal block may be retained on its trunnion by any suitable means (notshown). 45 is a chain connecting said claspv with the sprocket 41, tosupport the clasp within easy reach when it has been slipped off thetrunnion in changing drums. 46 is a sprocket chain for driving thesprocket 41 of the'drum 10. 47 is a guide roller for said chain,journaled on the end of-fa pivoted arm 47a impelled by an ad-` justableweight 47h, said roller thus being adapted to act as a chain tightenerand also to cause the chain to support the sprocket 41 in the positionshown in dotted lines in Fig. 8 when said sprocket is removed from thetrunnion in the changing of drums, as will presently be described.

Each of the journal blocks 36 of the drum 10" is removably mounted in avertical guide way in one of the end standards 33, one vertical side ofsaid guide-way being formed by a gate 48 pivoted at its lower end to thestandard 33, as indicated at 49, and adapted to be retained in anupright position by nuts 50, 50,0n studbolts projecting from saidstandard through slots 51, 51 in said gate, or to be turned about itspivot 49 to a horizontal position, as indicated in dot-anddash lines inFig.` 8, where it rests on a bracket-like projection 48t from thestandard. When so opened, said gate is adapted toA permit the removal ofthe drum 10, with the journal blocks 36 remaining on the trunnionsthereof, from said end standards, and to afford a trackway for saidblocks in this operation. The liner-guiding roll 2O has its axle-endsadjustably mounted in quickly detachable brackets, one ofv which isshown at 52 (Fig. 6), secured to the end standards 33, so that said rollmay readily be removed to permit the removal of `the drumV 10 and thesubstitution of another drum of the same or a different size, and may beadjusted from or toward lthe drum so ras to determine the point at`which the work will leave the latter.

For supporting each of the journal blocks 36 in their vertical guidewaysand pressing the drum 10, with a uniform, 'adjustable' pressure, towardthe hard roll 16, each of the end standards 33 is formed, directly belowthe guideway, with a vertical guideape'rture 53 (Fig. 10), in which isslidably mounted a sleeve 54 having an enlarged, internally threadedlower end portion 55 adapted to be engaged and urged upward by theforked end of a lever 56 pivoted on the standard at 57, and having aweight 58 slidably mounted on its opposite end portion, said weightbeing adapted `to be secured in adjusted' positions on said lever by aset screw 59. `60 is a bolt threaded through the enlarged end portion 55of thesleeve 54, eX-

tending upward through the latter, and adapted to supportfthe journalblock 36. 61 isa hand wheel 'secured to the lower end of said bolt, forvarying its position in the sleeve 54, so that the lever 56 may act in asubstantially horizontal position although drums of different size' beused, and so that the force of the Weight 58 as applied to the drum maybeat its maximum for a given setting of said weight, and substantiallyconstant notwithstanding irregularities in the form of the drum.

' For driving the hard roll 16 and the drum 10 at the same peripheralspeed, their respective sprocket chains 35 and 46 extend to a variablespeed device such as is shown in Fig. 12, where 62 is a drive shaftjournaled in a frame 62a and adapted through gears 63, 64 to drive asprocket 65 upon which the chain 46 is mounted. 66, 66 are a pair ofconical pulleys slidably and nonrotatably mounted upon said shaft andadapted to be moved from and toward each other, by levers 67, 67,pivoted on the frame 62a, to vary their effective diameter. 68 is adrive belt mounted thereonand on a pair of conical pulleys 69, 69, thelatter being 'slidably and non-rotatably mounted upon a shaft 70, onwhich is secured a. Sprocket 71 for the chain 35. Said pulleys 69, 69are adapted to be moved from and toward each other by the levers 67, tovary their effective diameter in inverse relation to variations in thatof th-e pulleys 66, so as to keep the belt 66 taut while varying therelative angular speeds of the roll 16 and the drum 10. 72 is a rightand left threaded screw journaled in the frame 621 and adapted toactuate the levers 67 to move the pulleys 66 and the pulleys 69oppositely upon their shafts.

F or assuring the timely separation of the bias-cut strips of stock fromthe knives l1 and the drum 10, so that they will flatly and Aaccuratelylie in position upon the liner 21, to be carried thereby onto Ytherewinding roll 21a, the drum 10, and the rubber strips 14 and fabricstrips 15 thereon, may be formed with a radial aperture 73 at a. pointunderlying the leading corner of each piece of the work, and anopen-ended or nozzled compressed-air pipe 74, leading from a source ofcompressed air (not shown) may be supported in position to register withsaid apertures successively as the drum revolves, so as to blow theleading corner of'each piece of stock from the drum at a point adjacentthe position at which the liner 21 leaves said drum.

In the operation of the apparatus, assuming that bias strips of fabricare to be cut of different widths from those last cut, the bolts 60 areturned to lower the journal blocks 36 onto the floors of their guideways, the enlarged ends of the sleeves 54 sustaining the force of theweights 53, the gates lll) 48 are opened, the clasp 42 and sprocket 41are removed from the trunnion of the drum 10, the sprocket beingpermitted to hang in the chain 46 as indicated in dotted lines in Fig.8, the brackets 52 with the guide roll 20 supported thereby are removed,and the drum 10 is Withdrawn from the apparatus, its journal blocks 36sliding on the gates 48 as indicated in dotsand-dash lines in Fig.4 8.By` a reversal of these operations, another drum of different size, orwith the knives 11 differently spaced thereon, is mounted in theapparatus, the gates 48 arel closed, the guide roll 2() remounted andadjusted, the sprocket. 41 and clasp 42 mounted on the trunnion of thenew drum, the bolts GO set up to lift the .new drum until one of itsknives lbears against the hard roll 1G and the levers 56 are forced to asubstantially horizontal position, and the Weights 5S on said levers maybe adjusted to provide a suitable pressure between the drum 1() and roll16.

If not previously attended to, the liner 21 is threaded about the guiderollsl `and drum as shown in Fig. 1 and started upon the liner reWinderroll 21% The variable speed mechanism, shown in Fig. 12, is adjusted soas to give equal peripheral speeds to the roll 16 anddrum 10. The stock1T is then carried around the hard roll 16 and started between it andthe drinn 1() as power is applied through the shaft (l2. The stock'isthen continuously fed and cut in bias lstrips by rotation of said rolland drum, and the cut strips are carried by the liner4 21 from the drum10 to the liner rewinding roll 21 and interwound with said liner on saidroll. The leading portion of each piece of stock being; dislodged fromthe drum by the jet of air from the pipe 74, the Weight of the stock issufficient to peel it from the drum througl'iout the rest of its area,and the pieces of stock are thus caused to lie accu rately in order uponthe liner 21 as the latter proceeds to the rewinding roll.

The Work lies snugly and without wrinkl es upon the hard roll 16, aroundwhich it passes to the cutting position, and the cushions 14 press itagainst said roll in'nnediately at each side of the knife as the latteris forced into it, as Well as throughout the space between successiveknives, along `the nip of the roll and drum, so that the knives, thecushions and the work all move together without wrinkling or buckling ofthe fabric under the action of the knives. The resiliency of the knifemountings and the cushions thus results in an accurate cutting of thestock, and this effect is also promoted by reason of the fact that theWork passes partly around the roll 1G before reaching the knives, beingheld to true form by contact with said roll, this arrangement being suchthat the stock may pass onto said roll under substantial tension Withoutsuch tension causing an excessive lateral pull upon the cutting edge ofthe knife. The liner 21also assists 1n roducing this effect by. holdingsnuglyV against the drum the. foremost part of thestrip being cut. p

Modifications maybe resorted to-Without departing from the scope of myinvention, and I do not wholly limit my claims tothe speci ticconstruction shown.

I claim:

l. In a cutter for sheet material, the combination of a rotary drum,aaiexible knife wound hclically uponsaid drum, means for holding said.knife under longitudinal tension upon said drum, avroll adapted t0 bepressed against said knife in face-to-edge contact, inacutting actionupon the` Work, and means independent `of theL contact of said' rollwith said knife for driving said drum and` said roll at the sameAperipheral speed. Y

2. In a-cutter for sheet material, the combination of aAknife-holdingdrum, ,a iiexible knife lWound hclically aboutsaid drum, a resilientbacking member under said knife, a yielding, work-pressing member onsaid drum adjacent said knife and having a oylindrical outer facesubstantially flush with the-cutting edge of said knife and a c lndricalroll adapted to coact with said rum in arotary cutting actionupon theWork, said drum being -of such size inirespect to the angle at whichsaid knife lies thereon that said `roll passes, from the last endportion of said knife beforeit again contacts the foremost end portionof said knife.

3. In a rotary cutter, the combination of a rotary, knife-holding drum,a set ofv knives mounted on said drum, cushion members under saidknives, yielding Worlesupportincg1 members .mounted on said drum betweensai knives, the cutting edges of said knives and the outer surfaces ofsaid members lying at approximately the same distance from the center ofsaiddrum, so as to hold the Work in substantially `true circular form,and a member adapted to coact with said drum in a cutting action bypressing the Work against said knives.

4. In a rotary cutter for sheet material, the combination of a rotary,knife-holdin drum, a knife mounted hclically on sai action by pressingthe work against said knife, guiding means so associated with said rollas to cause it to receive the work at a part of its circumference remotefrom the cutting position, and a cushion member on said drum adapted topress the work against said roll adjacent said knife. j

6. In a rotary cutter for sheet material, the combination ofa rotary,knife-holding drum, a knife mounted'helically on said drum, a cushionmember mounted on said drum and having a cylindrical outer surfacesubstantiallyv flush with the cutting edge of said knife, a roll adaptedtorpress the work against saidl knife and said cushion member, means fordriving said drum and roll, and means for so guiding a liner as to causeit to pass partly around said drum in contact j therewith to hold thework in position on said drum and subsequently to carry the work awayfrom said drum.

7. In a cutter for sheet material, the combination of a knife-holdingdrum, a set of flexible `knives wound helically about said drum,resilient backing members under said knives, a cylindrical roll adaptedto coact with said 'drum in a rotary cutting action upon the work, saiddrum being of such size in respect to the angle at which said knives liethereon that said roll passes from the last end portion of each knifebefore it again' Icontacts the foremost end portion of said knife,'andrmeans independent of the contact of-said'roll with said knives fordriving said.v roll and said drum at the same peripheral speed.

. 8.l In a rotary cutter the combination of a drum, a set of flexibleknives mounted obliquely thereon, means for holding said knives underlongitudinal tension, yieldingy backing members for said1 knives yonsaid drum, a roll adapted topress the work against said knives, andmeans for driving said roll and said drum atthe same periph? eralspeed.V V f V9.' In ak rotary cutter, the combination of an elongated,flexible cutting' member formed with a plurality of cutting edgesrunninglongitudinally thereof, a drumcenstituting a mounting for said cuttingmember and yadapted to seat the latter with one or another" of itsedges'in cutting position,

means lfor holding said cutting member under longitudinal tension uponsaid drum, a roll adapted to coact with said drum and the knife thereonin a rotary cutting action upon the work, and means for driving saidroll and said drum at the same peripheral speed.

10. In a cutter for sheet material, theV combination of an elongatedcutting member, a mounting therefor comprising a hard backing-memberformed with a surface' adapted freely to receive and seat said cuttingmember and to hold it against lateral displacement, means for holdingsaid cutting member under longitudinal tension upon said backing member,and Aa resilient backing-'member for said hard lbackingmember.

11. In a cutter for sheet material, the

combination of an elongated cutting member, a mounting thereforcomprising a rigid 12. In a cutter for sheet material, the

combination ofan elongated cutting member, a mounting thereforcomprising a rigid member formed with a groove, a resilientbacking-member for said cutting member lying in said groove, a hardbacking-member overlying said resilient member in said groove, said hardmember being adapted to seat said cutting member and to hold it againstlateral displacement, and means for holding said backing-members undercompression in said groove while permitting them to be furthercompressed by the cutting action.

f 13. Ina cutter for sheet material, the combination of a flexibleknife, a resilient backing therefor comprising a body of hard rubberadjacent the knife and a body of soft rubber underlying said hard rubberbody, and a rigid member' formed with a groove in which the backingmembers are seated, the hard rubber backing member being formed t0interlock with the knife against lateral displacement of the latter.

, 14C. In a cutter for sheet material, the combination of ak knife, anda resilient backing therefor comprisinga body of hard rubber adjacentthe knife and a body of soft rubber underlying said hard rubber body,

said hard rubber body and said soft rubber body being vulcanizedtogether.

415. In a cutter for sheet material, the comloinationl of a knife, and aresilient backing therefor, said backing comprising a body of hardrubber adjacent the knife, a metal reinforcement vulcanized in said hardrubber body, and a soft rubber body underlying said hardrubber body, thehard rubber portion of the backing being formed with a surface adaptedfreely to receive and to seat the knife and to interlock with 1t againstlateral displacement.

16. A rotary cutter comprising a drum formed with a helical groove, aresilient knife-backing member lying in sai-d groove, a hardknife-backing member overlying said resilient knife-backing-member insaid groove, a. long, flexible knife having a plurality of cutting edgesrunning lengthwise thereof, said knife being wound helically about saiddrum 4so as to `seat `upon said hard backing-member, means :forpreventing lateral displacement of said knife, and means for anchoringthe ends of said'knife at theends ofthe druniso as to hold said knife,by its longitudinal. tension, against 'said hard backing-member.

17. Ina rotary cutter, the combination of a drum formed. with a helicalgroove, a resilient knife-.backing member mounted .in said groove,andk alongflexible knife wound helically about said drum, overlying `saidbacking member,.and means for pulling the ends of said knifeeso as to`hold it against said backing member. v

V18. In a rotary cutter, the combination of a knife-holding drum, 4aknife mounted thereon, .a Aroll .adapted to press the Work lagainst saidknife, and stationary meansfor vdirectingva jet of air against saidworkat .a determinate, localized part of :the orbit of the .drum to`separate it from the drum..

:19. In a .rotary cutter for sheet material, the combination ofqa:knifediolding drum, ya set of knives Wound helically thereon, a rolladapted to press lsaid :material against said knives, the latter beingadapted to eut the material into bias strips, meansfordriv- ,ving saiddrum, and stationary means for directinga jet of air .againstthesuccessive stripsfat a determinate, localized part of the orbit ofthedrum as the drum is rotated to `.separate saidfstrips from said drum.

U20. In.y a' rotary y cutterl for sheet material,

'the combination of a knife-holding d rum, having its cylindrical Wallformed with a perforation, a knife` mounted on said drum,

a roll adapted to press the Work against said knife, means for drivingsaid drum, and an v.air Vconduit having an opening in positionto directAa jet of air periodically `into `said perforation as said drum isrotated.

.21. In arotary cutter, the combination of .a knife-holding drum, amounting therefor,

quickly-releasablemeans for holding said drum in said mounting, a rolladapted to coactfvvith said .drumin a rotary cutting faction, and ayvariable-speed' drivingmechanism operatively connecting ksaidroll and isaid drum.

A22. In-airotary cutter, the combination of 1a limife-holding drum,journal .blocks Vfor 4the -same,end. standards for said fdrum,:said

end standards being formed with vertical .guideways for said `journalblocks, means for yieldingly impelling said journal blocks `insaidguideways, and gate members forniing vertical side walls of saidguideways and 'adapted to be opened to. permit the removal of said drumfrom said end standards.

.23. Ina rotary cutter, the combination of a knife-holding drum, journal`blocks for the same, end-standards for said drum, said end-standardsbeing formed with vertical vgnideways for said vjournal-blocks, meansfor yieldingly impelling said journal blocks Ainlsaid guideways, a-stopfor said yielding means, means for adjusting the position of saidjournal-blocks with respect to said 4yielding' means, and pivotedgatemembers forming vertical side wal-ls of said :guideways, said Agatemembers being adapted to be opened out to permit the removal ,of saiddrum, with its journal blocks thereon, from said end standards, .and toserve as supports for said journal blocks asthe drun'i is withdrawn fromsaid endstandards- .24. In a rotary cutter, .thecombination of.aknife-holding drinn, end standards thereyfor adaptedforquick insertionand removal ofsaid drum, a roll adapted to coact With said drum in arotary cutting action, and a variable speed driving `mechanism oeratively yconnecting said roll and said dru1n,said mechanism vincludingquick-acting4 meansfor making or breaking the connection between said4roll saiddrum.

thereon that said rollpasses from the last end portion of said knifebefore vitagain contacts the rforemost endportion of said knife.

In Witness whereof I have hereunto set my hand this 20 day of May, 1922.

JOHN R.- GAMMETER.

